


Swimming with the fish

by MysteryFicAnon



Category: Undertale (Video Game)
Genre: Don't copy to another site, Implied/Referenced Torture, M/M, Mafiatale AU, MerMay, MerMay 2019, POV Alternating, Rating May Change, Slow Burn, Tags May Change, Unclear if it's super graphic or not, mafiatale, mermaid au, mermaid sans, some violence
Language: English
Status: In-Progress
Published: 2019-05-26
Updated: 2019-08-09
Packaged: 2020-03-19 22:46:50
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, No Archive Warnings Apply
Chapters: 4
Words: 3,536
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18979897
Author URL: https://archiveofourown.org/users/MysteryFicAnon/pseuds/MysteryFicAnon
Summary: Notorious mafioso Red ends up swimming with the fish, but it isn't what he expected...





	1. Slowly Drowning

The water was dark and bitingly cold. It rushed around him, pushing down on him with enough force to make his bones ache. If he had lungs, he would probably be dead by now. For now, Red was conscious for every second of the drop down. The concrete was pressing painfully against the bones of his feet, seeping through his shoes to thoroughly trap him. The tight chains meant that even if he had enough energy to muster up magic, he couldn’t properly direct it to form an attack. He was bound, trapped, and helpless.

He’d never pictured himself going out like this. Sure, there was the old mafia joke about “swimming with the fishes”, but everyone knew the chances of dusting in a fight were way higher. If only he’d been that lucky.

That was probably why the other gang had picked this for him: this fate would be even worse for a skeleton monster. He couldn't drown, so he would just starve to death at the bottom of the bay. With the size, depth, and underwater currents that ran through it, there was no way Boss was gonna find him in time. Any of his remains would be washed out to sea. He would never be seen again, and there would be no proof that he didn't just run away, trying to leave a life of crime behind. Hopefully Boss would be smart about this. Red felt he’d done a decent job of raising him, but there was nothing that could really quell the anxiety of leaving his baby brother behind. No more team, Boss didn't have anyone to watch his back…

He hadn't even realized his eyelights had guttered out until he hit the bottom. The impact rattled up through his femurs, and he let out a groan. Even without a tongue, the feeling of salt water filling his mouth was unpleasant. His magic sparked to life again, flickering unsteadily in the water.

He looked around. It was exactly what he’d expected. There was nothing but sand, rocks, and the chains holding him down. He was completely alone. Even the effort of keeping his eyes lit was starting to make him feel dizzy. This was bad. He needed to be smart about this, conserve his energy.

There was probably no chance in hell Boss would actually find Red, but his bro had won out against better odds before. Red just needed to stay calm and wait. He extinguished his eyelights, the water rushing in to resume its’ rightful place inside his skull. Oof, that was going to annoy him for the rest of his days.

Being in complete darkness was the worst. There was nothing at all, not even sound to distract him. He could not help thinking, running all the possible scenarios through his mind. There weren't a lot of them where he came out ok in the end.

Oh shit, he hadn’t left behind a will. Boss was going to have a hell of a time sorting through his room, let alone figuring out who would want to keep all his shit. He would finally find all those old baby pictures Red kept in the shoebox under his mattress. Fuck, Red hoped he wouldn't burn them. It had been hell to actually get his hands on a camera the first place, and those photos were the cutest fucking thing he’d ever seen. Now, he would never be able to look at them again…

It took him a depressingly long time to realize something had changed. He jerked his head around, his eyes blazing bright as he squinted, desperately trying to see. After a moment, the source of the light crept out from behind a nearby rock.

Well, apparently hallucinations were going to be a thing now. Sure, when monsters had come out of the mountain the humans had told them stories about “mermaids” that were part human and part fish, but they weren’t REAL. Besides, this freaky fish looked like it was part skeleton, complete with a glimmering ecto-tail and small, fin-like slits along his ribs.

The last thought he had before passing out was that the thing was swimming awfully close to him…


	2. The Morning After

**Summary for the Chapter:**

> Miraculously, Red wakes up.
> 
> Trigger warnings for this chapter: some discussion of Red's injuries, Sans uses manipulative magic (he's a siren so like... it kind of comes with the territory for me)
> 
> Also: shoutout to @thycutterofmuchcookiez on Tumblr for beta reading this! I appreciate it :)

For a good minute, Red wasn’t sure where he was. He was laying on something soft and damp…  He was laying on something soft and damp. Had he spilled beer on his mattress again? Fuck, was that why it felt like every bone in his body had been stomped on? He couldn’t remember fighting last night-Oh shit.

He sat up too quickly and white light exploded across his vision as he wheezed. He moved to lie back down, his bed squishing disgustingly as he slowly relaxed against it. Whatever this thing was, it sure as hell wasn’t a mattress. It felt slimy, and under a thin layer of soft, Red could feel cold stone digging into his spine.

He laid there for a few minutes, breathing slowly. It was still too dark for him to see, but his breath was echoing faintly in the space. It must be pretty cramped in here, he was lucky he hadn’t cracked his skull when he’d tried to sit up. There was water lapping at the shore somewhere nearby too. He wasn’t out of the woods just yet…

He decided to take stock. His wrists were sore, but the chains were gone. Out of everything, his feet were aching the worst. He looked down, wincing a little. The magic between his joints illuminated the fine spider web of fractures wrapping around his tarsals and spreading out to his phalanges. Irritated red magic throbbed between the cracks in the bone. It was clear he wouldn't be walking for a couple days.

Red chuckled. After all the shit he’d been through, he welcomed the chance to put his feet up for a little bit. His laughter echoed louder in the cramped space, but suddenly, the smile dropped from his face. Shit. He wouldn't get Boss’ snarky comments or healing touch to help him out this time...Wherever he was.

He rolled over onto his side, staring blankly at the darkness. He reached out, lightly feeling the stone in front of him. It was slightly damp, the rough rock scraping over the points on his phalanges. He let out a jump as he came into contact with water, quickly pulling his hand back. The fuck? Was there an ocean next to him?

The scraping of his phalanges must have startled something hidden in the black, because a sudden blue glow illuminated the room . He scooted back as much as he could, watching nervously as the water began to glow even brighter. After so long in the dark it was incredibly bright, and Red’s eyelights shrunk as he tried to adjust to the new light. He could hear the water moving a little, and he shifted backwards.

“Stay back!” His own voice sounded high-pitched to him, the pathetic desperation of someone backed into a corner horribly clear. He tried his best to move, but let out another wheeze of pain.

He couldn't get much farther, and a few feet away from the water wouldn't be enough to protect him from anything. He took a deep breath, trying desperately to summon some sort of attack. If he was going down, then he was going to take this motherfucker out with him, damn it!

A single, shaking bone appeared, lighting up the cavern even more. Red had been right earlier, the patch of ground he was sitting on was barely a rocky ledge. There was no openings in the ceiling, and barely any space to maneuver. Even if he did beat his attacker, he would have to swim and face any others lurking nearby.

Fuck, he really was screwed.

He glared at his attack, but even the red glow of his magic was beginning to dim. Could this thing even shave off one point of HP? It didn't matter. It was all Red had. He turned his gaze back to the water, getting ready to strike. This was a coward’s blow, but he couldn't afford to do anything else.

Of all the things he’d guessed would emerge from the water, the smooth skull with ecto-fins attached to it was not one of them. Red stared, a few hazy memories from right before he passed out coming back to him. The thing cocked its head, letting out a little hum. The noise was incredibly lovely, echoing a little off the cave walls. Even if Red didn't speak the language this thing was using, he could  **feel** the intent behind the sound, the gentle curiosity somehow managing to put him more at ease.

His entire life he’d been surrounded by LV and malicious intent. Even when they'd left the dusty air of the Underground behind, the killing and scheming never stopped. The only person Red could trust was his own brother, and even Boss kept him on his toes. Apparently, he thought surface life would make Red “grow soft.” If the three new points to his LV were any indication, he hadn’t.

This creature was different though. Even without checking it, Red could feel nothing but the intent to calm. It kept humming, the steady stream of sounds coming together in a beautiful melody. The echoes of the previous notes that hadn’t quite faded provided a harmony, each tone coming together perfectly. Red hadn’t even noticed that he’d dissipated the attack with a quick swipe of his hand, too caught up in watching as the thing approached. It swam slowly, each movement in time with the music.

Once it reached the edge of the rocky edge, the song began to subtly shift. It didn't get any quieter, but suddenly the intent to calm was a lot stronger. The change hit Red like a brick to the face, his tiredness coming back in a wave. The pain of his aches was dulled into numbness, the kind of exhaustion that got inside his marrow and weighed down his bones.

Red shifted sluggishly, squinting as he struggled to keep his eyes open. Maybe he should just lie down, get some more rest. His new companion seemed to agree with that, the singing growing in force when Red leaned back against the soft mattress. A little nap couldn't hurt. He would deal with things when he woke up again…

Red closed his eyes, barely able to feel cold bones brush against his forehead before he was out like a light.


	3. Rocky Shores

**Summary for the Chapter:**

> We get a look at events from someone else's perspective.
> 
> Trigger warnings for this chapter: mentions of murder/death/hostage situations
> 
> Shoutout to @thycutterofmuchcookiez on Tumblr for beta reading this again!

Edge was not a monster of faith. Ever since he was a child, he’d learned the hard way that it didn’t pay to put trust into anything uncertain. Perhaps that was what made this all the more difficult. As much as he wanted to believe that his brother was alive somewhere, just lying low until the heat died down, he couldn’t fully convince himself. It sounded too much like the delusional desperation of a monster unable to accept their loss.

These were the facts: Red had gone missing almost three days ago. Before that, Edge had received an anonymous phone call threatening him from a member of a different gang warning him to stay out of the local business. He’d followed a few leads, and managed to learn that a fishing boat had been rented and gone out into the bay at three in the morning on the night of Red’s disappearance.

Undyne was working on tracking down the humans who’d been on the boat. Red had always been the one in charge of their network of information and without him tracking down leads was even more difficult. And since he was clearly the target, Edge was ordered to stand down for now.

He should be sleeping, but he never had much need for it. And sitting around a far too clean and empty house would not help matters.

So here he stood, at the edge of the bay whose waters had probably swallowed up his brother. He stared out at the waves in front of him, the water stretching out into the horizon.

It looked surprisingly mundane. Edge looked down at the ground, kicking it a little. There was a little sand mixed in with the rocks, but this wasn’t the dusty shore of any lake or river back in the Underground. Life up here wasn’t a breeze, but things were undeniably easier up on the Surface. It was almost enough to make Edge to relax, or so he had thought.

For all his warnings to Red about growing complacent, Edge had been blinded. He had never expected something like this to happen to him. Since they’d left the Underground, both brothers had made themselves useful to some very powerful people. They had more connections now than they ever did below the Surface, and humans were far more likely to keep their word.

Here was the consequence of lowering his guard: his brother had disappeared. 

Red was often fond of teasing Edge about his ego, but he was also the one who’d kept Edge in check. He should have known better than to believe they were untouchable. Red had known about the call, of course, but Edge should have done more to make sure they were both protected.

His introspection was broken by a faint noise that was barely audible over the waves. Edge could distinctly make out the sound of something clicking against the rocks. He took a step back, looking around as best he could without turning his head. He couldn't see anything, but that didn't mean that he wasn't alone.

He reached for his hidden holster, placing one hand on his gun. Monsters weren’t supposed to use magic on humans, and Edge wasn’t about to break that rule on a suspicion. Besides, leather gloves got rid of any pesky gun residue if he needed to shoot.

He looked around again, turning slowly. The nearest cliff was too far away for a sniper, and Edge could see nothing close by. He stared out at the water again, but there wasn't anything except light shining off the waves.

Edge took a deep breath and turned around. There was no point in lingering. He had work to do. Even if it was difficult to keep faith, Edge was going to find his brother, and angel help anyone who stood in his way.


	4. Song of the Sea

**Summary for the Chapter:**

> Red wakes up again, and Sans has something to say.
> 
> Some trigger warnings: minor injuries and mentioned life-threatening peril (on Red's part)
> 
> Shoutout to @thycutterofmuchcookiez on Tumblr for beta reading!

Red wasn’t sure how long he slept for, but every once in a while he could remember waking up to soft blue lights and more of that wonderful humming. Someone might have trickled water into his jaw a couple of times, but everything was incredibly fuzzy. His body still ached, but each hour of sleep seemed to help a little bit.

When he finally woke up for real, he was lying on his side in a bed of now-dry plants. They rustled a little as he moved, cracking one eye socket open to look around. He was still in the same cave, suspended in timeless darkness. He flared his eyelights a little brighter, squinting to try and see.

There was a small carved bowl next to him, and he reached out and tentatively dipped his fingers into it. The liquid inside felt blissfully cool, and he eagerly dragged it over. His entire body felt dry and crusty, and his mouth felt like a desert.

Water had never tasted so good. He slurped greedily, spilling some of it over his face and neck. He let out a pleased groan, drinking until his face was scraping against the bottom of the bowl. He set it down next to him, shifting to lie on his back. He wasn't tired enough to sleep yet, but that much movement had drained him. He closed his eyes, letting out a sigh. The water had been filling, but his magic was calling out for more. He could really go for some food right now, especially something packed with Boss’ healing intent…

The pool of water next to him sloshed, and suddenly there was a soft clicking sound near him. Red stiffened up, slowly cracking one eye socket. The strange skeleton-mermaid was back, picking up the empty bowl. Red stiffened up for a moment, but then forced himself to relax. He might have been a paranoid bastard, but he had to acknowledge that the mermaid wouldn’t put in that much care unless he wanted him alive for something. For now, he tentatively decided to trust the mermaid.

“Hey. It’s you.” After a few days of not using his voice it was a little rough, but Red hoped the mermaid could understand him. He grunted, turning on his side again so he was facing the mer-skeleton. It was still freaky as hell to see the creature just sitting there, but after all the help he’d gotten, Red felt like he owed it to the thing to at least try and be polite.

The mermaid nodded, and began to speak. Well, Red guessed that was what he was doing. He was making sounds, but Red couldn't understand the garbled language. Red could still sense the undercurrent of magic that was present in his singing, but it wasn’t as prominent. He had no idea what the mermaid had just said, but it would be rude not to answer…

“Er, that's cool. My name’s Red.” He smiled awkwardly, giving a little wave.

“Rrrred.” The skeleton said, pointing at him. Then, he made a strange trilling noise, pointing at himself. It kind of sounded like a name.

“You’re… Sans?” Red asked, hoping that he didn't butcher the name.

Sans nodded, smiling brightly at him. “Rrrred, Sans.” He said, pointing at both of them. He pulled himself a little farther out of the water, stretching his hand towards Red.

It took Red a second to realize that Sans was reaching out for a handshake. He awkwardly reached out, grabbing Sans’ hand and shaking it. Aside from being slightly damp, Sans’ bones felt just like any other skeleton’s would. It was a little weird, but Sans seemed very pleased with it.

After the handshake went on just long enough for Red to be uncomfortable, Sans let go and moved back. He reached into the water, pulling up a small bag and opening it. He extracted a small, round object from it and held it out towards Red. He wiggled it a little, clearly trying to entice Red in to taking it.

“Er, thanks.” Red said, awkwardly holding the thing. His phalanges sunk in to it a little, and it appeared to be some kind of green sponge. He held it, looking at Sans. Was this… something to wash himself with? Did Sans expect him to do it while he sat there?

Sans sighed, shaking his head. He seemed a little amused at Red’s confusion, but he didn't try and say anything to Red. Instead, he reached out and took the squishy ball back. He held it up to his mouth, mimed taking a bite, and then handed it back to Red.

Red inspected the thing again. It looked like a plant, but it didn’t resemble anything Red had eaten Underground or on the Surface. Strange as it was, Red couldn't really refuse it. He was starving, and he needed to eat something. If he couldn't handle it, then at least things would be over quickly…

He bit down, letting out a grunt of surprise as he felt the first surge of healing magic run through him. He quickly shoved the entire thing in his mouth, shuddering as he felt even more magic coursing through him. He didn’t even have to check his stats to know that his HP was going back up. When he glanced down, the cracks on his feet looked a little less raw.

“Thanks,” Red said, with genuine gratefulness this time.

Sans smiled at him but after a moment he paused, his tail twitching. Without warning he pushed himself back, sliding down in to the water. He ducked back underneath the surface, and seemed to tilt his head to the side and listen to something. He popped back up, once again saying something in his trilling voice.

Red might not have been able to understand Sans’ words, but he could still read the guy’s face. So, when Sans smiled apologetically and gestured downwards, he could guess that Sans was being called. He might want to spend a little more time with Red, but he had to go.

“Ah, don’t worry about it. Go ahead.” Red said, waving a hand dismissively. He didn't expect Sans to stay with him 24/7. If one mer-monster existed, then there were probably more of them.

Sans nodded and reached into his bag. He pulled out a few more of the healing plants, set them in the empty bowl and put a small jug down next to it. He waved, then dived down again. Red leaned over to check, but he’d already swam away.

Red laid back down, shuffling around to try and get comfortable. He wasn’t tired enough to sleep yet, but that wasn't a problem. Now that he knew for certain that the mermaid was real, he had quite a few things to think about…


End file.
